powerpc/mpc85xx: SECURE BOOT- Add secure boot target for T4240QDS and T4160QDS

Secure Boot Target is added for T4240QDS and T4160QDS
Changes:
For Secure boot, CPC is configured as SRAM and used as house
keeping area which needs to be disabled.
So CONFIG_SYS_CPC_REINIT_F is defined for CONFIG_T4240QDS.

Signed-off-by: Aneesh Bansal <aneesh.bansal@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>